Question

A student pushes a 50 kg box of books on a flat surface with a force of 120 N at an angle of 60° on the horizontal. If the surface is friction free, how far does the box move in 5 seconds assuming it started moving from rest? a. 6.0 m
b. 8.5 m
c. 15 m
d. 4.6 m

Answer 1

Answer:

c. 15 m

Explanation:

We apply Newton's second law in the x direction:

∑Fₓ = m*a

120*cos(60°) = 50*a

$a = \frac{120*cos(60^o)}{50}  = 1.2 \frac{m}{s^2}$

Block kinematics

The block moves with uniformly accelerated movement, so we apply the following formula to calculate the distance

$d = V_o*t + \frac{1}{2}*a*t^2$

$d = 0 + \frac{1}{2}*1.2*5^2$

d = 15m